HYM - Displacement

Owned by thomas (Unlicensed)
Last updated: 27 Nov, 2014
3 min read

A Hybrido fluid's displacement can be seen as an additional layer on top of the main body of water. This layer adds small waves and ripples to the surface and provides extra realism. In order to use this feature with a simulation, it has to be activated manually under the Hybrido domain's “Ocean Statistical Spectrum” panel. This height information is used to displace the mesh's vertices.

If your core fluid simulation has been simulated without displacement, this parameter set can be ignored. Please bear in mind that this option is very RAM-intensive and creates very large meshes – several million polygons per frames are absolutely normal. The parameters of the "Displacement" panel support the "Interactive Meshing" feature.

 

 

Auto edge length

This option uses the Hybrido Domain's “Quality” parameter from the “Displacement” channel to control the resolution at the mesh's edges. An example: With a “Quality” value of 512, the mesh's edges are subdivided until there are 512 triangles at each side. For this process, the domain's projection plane is used. When set to “No” the “@ edge length” parameter is unlocked where you can define the edge length manually.

@ edge length

This parameter is only accessible when “Auto edge length” is disabled (“No”). The value given here will be used by the HyMesh engine to define the length of the mesh's border triangles. The final number of edge triangles, on the other hand, is then calculated from this length. The value is measured in metres [m]

Use displacement

If you want to bake the displacement information to the mesh enable this option.

Height attenuation

If you want to consider the vertices' heights to fade the displacement please activate this option.

@ height normalization factor

A fluid's height values can cover a very broad range and therefore, the values have to be normalized. Normalization means that all values are set in relation to a constant value: the normalization factor you enter here. With 1.0, for example, all height values will range between 0 and 1.

@ height min/@ height max

With these parameters it is possible to define a range: vertices, with height values smaller than “@ height min” will not be affected. If a vertex' height value is greater than “@ height max” then it receives full attenuation. Between these extremes, attenuation is applied gradually

Speed attenuation

If you want to consider the vertices' speed to fade the displacement please activate this option.

@ speed normalization factor

In most simulations, velocity values cover a very broad range of values, e.g. from 0 m/s to 23.7 m/s. These ranges are difficult to handle and therefore they are normalized. After this process, all velocities will be between 0 and 1. With this factor you can “amplify” the normalized values, because they will be multiplied with the given "@ speed min/max" values.

@speed min/@ speed max

With these parameters it is possible to define a range: vertices, with speed magnitudes smaller than “@ speed min” will not be affected. If the speed magnitude is greater than “@ speed max” then it receives full attenuation. Between these extremes, attenuation is applied gradually.

Splash attenuation

“Splash attenuation” means that in those areas of the core fluid that behave more like splashes the displacement fades, and finally vanishes. These areas normally do not need any displacement at all.

@ splash attenuation factor

With this parameter it is possible to make the displacement patterns vanish faster (> 1) or slower (< 1).

Vorticity attenuation

Here, vorticity can be used to fade, and finally remove the displacement. Please bear in mind that the grid domain's “Vorticity” channel has to be activated before the simulation starts, because otherwise this option does not have any effect at all. By default, the “Vorticity” channel is disabled:

 HY_Domain node > Node Params > Particle Channels > Vorticity

@ vorticity normalization factor

A fluid's vorticity values can cover a very broad range and therefore, the values have to be normalized. Normalization means that all values are set in relation to a constant value: the normalization factor you enter here. As a result, all vorticity values will range between 0 and 1.

@ vorticity attenuation factor

With this parameter it is possible to make the displacement patterns vanish faster (> 1) or slower (< 1).